1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_SHARED_C2_BARRIERSETC2_HPP 26 #define SHARE_GC_SHARED_C2_BARRIERSETC2_HPP 27 28 #include "memory/allocation.hpp" 29 #include "oops/accessDecorators.hpp" 30 #include "opto/loopnode.hpp" 31 #include "opto/memnode.hpp" 32 #include "utilities/globalDefinitions.hpp" 33 34 // This means the access is mismatched. This means the value of an access 35 // is not equivalent to the value pointed to by the address. 36 const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1; 37 // The access may not be aligned to its natural size. 38 const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2; 39 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed, 40 // but never false positives. 41 const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3; 42 // This denotes that a load has control dependency. 43 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4; 44 // This denotes that a load that must be pinned. 45 const DecoratorSet C2_PINNED_LOAD = DECORATOR_LAST << 5; 46 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics. 47 const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6; 48 // This denotes that the access mutates state. 49 const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7; 50 // This denotes that the access reads state. 51 const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8; 52 53 class GraphKit; 54 class IdealKit; 55 class Node; 56 class Type; 57 class TypePtr; 58 class PhaseMacroExpand; 59 60 // This class wraps a node and a type. 61 class C2AccessValue: public StackObj { 62 protected: 63 Node* _node; 64 const Type* _type; 65 66 public: 67 C2AccessValue(Node* node, const Type* type) : 68 _node(node), 69 _type(type) {} 70 71 Node* node() const { return _node; } 72 const Type* type() const { return _type; } 73 74 void set_node(Node* node) { _node = node; } 75 }; 76 77 // This class wraps a node and a pointer type. 78 class C2AccessValuePtr: public C2AccessValue { 79 int _alias_idx; 80 81 public: 82 C2AccessValuePtr(Node* node, const TypePtr* type) : 83 C2AccessValue(node, reinterpret_cast<const Type*>(type)) {} 84 85 const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); } 86 int alias_idx() const { return _alias_idx; } 87 }; 88 89 // This class wraps a bunch of context parameters thare are passed around in the 90 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate. 91 class C2Access: public StackObj { 92 protected: 93 GraphKit* _kit; 94 DecoratorSet _decorators; 95 BasicType _type; 96 Node* _base; 97 C2AccessValuePtr& _addr; 98 Node* _raw_access; 99 100 void fixup_decorators(); 101 void* barrier_set_state() const; 102 103 public: 104 C2Access(GraphKit* kit, DecoratorSet decorators, 105 BasicType type, Node* base, C2AccessValuePtr& addr) : 106 _kit(kit), 107 _decorators(decorators), 108 _type(type), 109 _base(base), 110 _addr(addr), 111 _raw_access(NULL) 112 { 113 fixup_decorators(); 114 } 115 116 GraphKit* kit() const { return _kit; } 117 DecoratorSet decorators() const { return _decorators; } 118 Node* base() const { return _base; } 119 C2AccessValuePtr& addr() const { return _addr; } 120 BasicType type() const { return _type; } 121 bool is_oop() const { return _type == T_OBJECT || _type == T_VALUETYPE || _type == T_ARRAY; } 122 bool is_raw() const { return (_decorators & AS_RAW) != 0; } 123 Node* raw_access() const { return _raw_access; } 124 125 void set_raw_access(Node* raw_access) { _raw_access = raw_access; } 126 virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses. 127 128 MemNode::MemOrd mem_node_mo() const; 129 bool needs_cpu_membar() const; 130 131 template <typename T> 132 T barrier_set_state_as() const { 133 return reinterpret_cast<T>(barrier_set_state()); 134 } 135 }; 136 137 // This class wraps a bunch of context parameters thare are passed around in the 138 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate. 139 class C2AtomicAccess: public C2Access { 140 Node* _memory; 141 uint _alias_idx; 142 bool _needs_pinning; 143 144 public: 145 C2AtomicAccess(GraphKit* kit, DecoratorSet decorators, BasicType type, 146 Node* base, C2AccessValuePtr& addr, uint alias_idx) : 147 C2Access(kit, decorators, type, base, addr), 148 _memory(NULL), 149 _alias_idx(alias_idx), 150 _needs_pinning(true) {} 151 152 // Set the memory node based on the current memory slice. 153 virtual void set_memory(); 154 155 Node* memory() const { return _memory; } 156 uint alias_idx() const { return _alias_idx; } 157 bool needs_pinning() const { return _needs_pinning; } 158 159 void set_needs_pinning(bool value) { _needs_pinning = value; } 160 }; 161 162 // This is the top-level class for the backend of the Access API in C2. 163 // The top-level class is responsible for performing raw accesses. The 164 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle 165 // barriers into the accesses. 166 class BarrierSetC2: public CHeapObj<mtGC> { 167 protected: 168 virtual void resolve_address(C2Access& access) const; 169 virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const; 170 virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const; 171 172 virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val, 173 Node* new_val, const Type* val_type) const; 174 virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val, 175 Node* new_val, const Type* value_type) const; 176 virtual Node* atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const; 177 virtual Node* atomic_add_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const; 178 179 public: 180 // This is the entry-point for the backend to perform accesses through the Access API. 181 virtual Node* store_at(C2Access& access, C2AccessValue& val) const; 182 virtual Node* load_at(C2Access& access, const Type* val_type) const; 183 184 virtual Node* atomic_cmpxchg_val_at(C2AtomicAccess& access, Node* expected_val, 185 Node* new_val, const Type* val_type) const; 186 virtual Node* atomic_cmpxchg_bool_at(C2AtomicAccess& access, Node* expected_val, 187 Node* new_val, const Type* val_type) const; 188 virtual Node* atomic_xchg_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const; 189 virtual Node* atomic_add_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const; 190 191 virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const; 192 193 // These are general helper methods used by C2 194 virtual bool array_copy_requires_gc_barriers(BasicType type) const { return false; } 195 196 // Support for GC barriers emitted during parsing 197 virtual bool has_load_barriers() const { return false; } 198 virtual bool is_gc_barrier_node(Node* node) const { return false; } 199 virtual Node* step_over_gc_barrier(Node* c) const { return c; } 200 201 // Support for macro expanded GC barriers 202 virtual void register_potential_barrier_node(Node* node) const { } 203 virtual void unregister_potential_barrier_node(Node* node) const { } 204 virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { } 205 virtual void enqueue_useful_gc_barrier(Unique_Node_List &worklist, Node* node) const {} 206 virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful) const {} 207 virtual void add_users_to_worklist(Unique_Node_List* worklist) const {} 208 209 // Allow barrier sets to have shared state that is preserved across a compilation unit. 210 // This could for example comprise macro nodes to be expanded during macro expansion. 211 virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; } 212 // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be 213 // expanded later, then now is the time to do so. 214 virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; } 215 virtual void verify_gc_barriers(bool post_parse) const {} 216 }; 217 218 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP